Thrust Reverser Actuation Systems (TRAS) power and control the deployment of aircraft thrust reversers. Thrust reversal, also called reverse thrust, involves the temporary diversion of a jet aircraft's exhaust so that it acts against the forward travel of the aircraft, providing deceleration, for example, to help slow an aircraft after touch-down. Such devices are considered important for safe operations by airlines.
However, such devices can also negatively affect the operation of an aircraft if they are misused or malfunction. A number of aircraft accidents have been traced back to accidental TRAS deployments. As such, many TRAS designs include locking mechanisms to ensure that the TRAS remains stowed until needed. Many of these systems utilize large bias springs to bias locks toward the locked position and to overcome vibration and air load forces, and use hydraulic linear actuators with high power densities to overcome the bias springs in order to release the lock. Such systems add weight and consume space, both of which can be limited, especially in aircraft applications.